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http://dx.doi.org/10.1590/1678-775720130359
Influence of light-exposure methods and depths of cavity on the microhardness of dual-cured core build-up resin composites Keiichi YOSHIDA1, Xiangfeng MENG2 1- Clinic of Fixed Prosthodontics, Nagasaki University Hospital, Nagasaki, Japan. 2- Department of Prosthodontics, The Stomatological Hospital Affiliated Medical School, Nanjing University, Nanjing, China. Corresponding address: Keiichi Yoshida - Clinic of Fixed Prosthodontics - Nagasaki University Hospital, 1-7-1 - Sakamoto, - Nagasaki - 852-8588 - Japan - Phone: +81-95-819-7688 - Fax: +81-95-819-7689 - e-mail: [email protected] Submitted: May 26, 2013 - Modification: August 19, 2013 - Accepted: September 18, 2013
abstract
O
bjective: The purpose of this study was to evaluate the Knoop hardness number (KHN) of dual-cured core build-up resin composites (DCBRCs) at 6 depths of cavity after 3 post-irradiation times by 4 light-exposure methods. Material and Methods: Five specimens each of DCBRCs (Clearfil DC Core Plus [DCP] and Unifil Core EM [UCE]) were filled in acrylic resin blocks with a semi-cylindrical cavity and light-cured using an LED light unit (power density: 1,000 mW/cm2) at the top surface by irradiation for 20 seconds (20 s), 40 seconds (40 s), bonding agent plus 20 seconds (B+20 s), or 40 seconds plus light irradiation of both sides of each acrylic resin block for 40 seconds each (120 s). KHN was measured at depths of 0.5, 2.0, 4.0, 6.0, 8.0, and 10.0 mm at 0.5 hours, 24 hours, and 7 days post-irradiation. Statistical analysis was performed using repeated measures ANOVA and Tukey’s compromise post-hoc test with a significance level of p0.05). However, at 24 hours and 7 days post-irradiation, the B+20 s method resulted in significantly higher KHN values than the 20 s method at all depths of cavity, except 0.5 mm (p
http://dx.doi.org/10.1590/1678-775720130359
Influence of light-exposure methods and depths of cavity on the microhardness of dual-cured core build-up resin composites Keiichi YOSHIDA1, Xiangfeng MENG2 1- Clinic of Fixed Prosthodontics, Nagasaki University Hospital, Nagasaki, Japan. 2- Department of Prosthodontics, The Stomatological Hospital Affiliated Medical School, Nanjing University, Nanjing, China. Corresponding address: Keiichi Yoshida - Clinic of Fixed Prosthodontics - Nagasaki University Hospital, 1-7-1 - Sakamoto, - Nagasaki - 852-8588 - Japan - Phone: +81-95-819-7688 - Fax: +81-95-819-7689 - e-mail: [email protected] Submitted: May 26, 2013 - Modification: August 19, 2013 - Accepted: September 18, 2013
abstract
O
bjective: The purpose of this study was to evaluate the Knoop hardness number (KHN) of dual-cured core build-up resin composites (DCBRCs) at 6 depths of cavity after 3 post-irradiation times by 4 light-exposure methods. Material and Methods: Five specimens each of DCBRCs (Clearfil DC Core Plus [DCP] and Unifil Core EM [UCE]) were filled in acrylic resin blocks with a semi-cylindrical cavity and light-cured using an LED light unit (power density: 1,000 mW/cm2) at the top surface by irradiation for 20 seconds (20 s), 40 seconds (40 s), bonding agent plus 20 seconds (B+20 s), or 40 seconds plus light irradiation of both sides of each acrylic resin block for 40 seconds each (120 s). KHN was measured at depths of 0.5, 2.0, 4.0, 6.0, 8.0, and 10.0 mm at 0.5 hours, 24 hours, and 7 days post-irradiation. Statistical analysis was performed using repeated measures ANOVA and Tukey’s compromise post-hoc test with a significance level of p0.05). However, at 24 hours and 7 days post-irradiation, the B+20 s method resulted in significantly higher KHN values than the 20 s method at all depths of cavity, except 0.5 mm (p
